diff --git a/packages/build/src/extensions/prisma.ts b/packages/build/src/extensions/prisma.ts
index b67adc7efc..f18d9f08be 100644
--- a/packages/build/src/extensions/prisma.ts
+++ b/packages/build/src/extensions/prisma.ts
@@ -2,8 +2,9 @@ import { BuildManifest, BuildTarget } from "@trigger.dev/core/v3";
 import { binaryForRuntime, BuildContext, BuildExtension } from "@trigger.dev/core/v3/build";
 import assert from "node:assert";
 import { existsSync } from "node:fs";
-import { cp, readdir } from "node:fs/promises";
+import { cp, readdir, readFile } from "node:fs/promises";
 import { dirname, join, resolve } from "node:path";
+import { readPackageJSON, resolvePackageJSON } from "pkg-types";
 
 export type PrismaExtensionOptions = {
   schema: string;
@@ -102,12 +103,60 @@ export class PrismaExtension implements BuildExtension {
       (external) => external.name === "@prisma/client"
     );
 
-    const version = prismaExternal?.version ?? this.options.version;
+    let version = prismaExternal?.version ?? this.options.version;
 
+    // If still no version, try to read from installed node_modules
     if (!version) {
-      throw new Error(
-        `PrismaExtension could not determine the version of @prisma/client. It's possible that the @prisma/client was not used in the project. If this isn't the case, please provide a version in the PrismaExtension options.`
-      );
+      // First, try to read the actual installed @prisma/client version
+      const installedPrismaPath = join(context.workingDir, "node_modules", "@prisma", "client", "package.json");
+      if (existsSync(installedPrismaPath)) {
+        try {
+          const installedPkg = await readPackageJSON(installedPrismaPath);
+          if (installedPkg?.version) {
+            version = installedPkg.version;
+            context.logger.debug(
+              `PrismaExtension resolved version from node_modules: ${version}`
+            );
+          }
+        } catch (e) {
+          context.logger.debug("Failed to read @prisma/client from node_modules", { error: e });
+        }
+      }
+
+      // If still no version, check for catalog/workspace references and provide helpful error
+      if (!version) {
+        const packageJsonPath = await resolvePackageJSON(context.workingDir);
+        let errorDetail = "";
+
+        if (packageJsonPath) {
+          const pkg = await readPackageJSON(packageJsonPath);
+          const versionSpec = pkg.dependencies?.["@prisma/client"] ||
+                             pkg.devDependencies?.["@prisma/client"];
+
+          if (versionSpec?.startsWith("catalog:")) {
+            errorDetail = `Found pnpm catalog reference "${versionSpec}". `;
+          } else if (versionSpec?.startsWith("workspace:")) {
+            // Handle workspace: protocol - strip prefix and use the version if it's explicit
+            const stripped = versionSpec.replace("workspace:", "").trim();
+            if (stripped && stripped !== "*" && stripped !== "^" && stripped !== "~") {
+              version = stripped;
+              context.logger.debug(
+                `PrismaExtension resolved version from workspace protocol: ${version}`
+              );
+            } else {
+              errorDetail = `Found workspace reference "${versionSpec}". `;
+            }
+          }
+        }
+
+        if (!version) {
+          throw new Error(
+            `PrismaExtension could not determine the version of @prisma/client. ${errorDetail}` +
+            `When using pnpm catalogs or workspace protocols, please provide an explicit version in the PrismaExtension options: ` +
+            `prismaExtension({ version: "6.14.0", ... })`
+          );
+        }
+      }
     }
 
     context.logger.debug(`PrismaExtension is generating the Prisma client for version ${version}`);
diff --git a/packages/cli-v3/src/build/externals.ts b/packages/cli-v3/src/build/externals.ts
index c35f90cf18..472d155581 100644
--- a/packages/cli-v3/src/build/externals.ts
+++ b/packages/cli-v3/src/build/externals.ts
@@ -215,6 +215,17 @@ function createExternalsCollector(
                 return undefined;
               }
 
+              // Verify we found the right package.json (not a parent workspace)
+              if (packageJson.name !== packageName) {
+                logger.debug("[externals][onResolve] Found package.json but name doesn't match", {
+                  expected: packageName,
+                  found: packageJson.name,
+                  packageJsonPath,
+                  external,
+                });
+                return undefined;
+              }
+
               if (!external.filter.test(packageJson.name)) {
                 logger.debug("[externals][onResolve] Package name does not match", {
                   external,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 6c7ca99a06..db35d4dfdd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -28921,7 +28921,7 @@ packages:
       lilconfig: 2.1.0
       postcss: 8.4.29
       ts-node: 10.9.1(@swc/core@1.3.26)(@types/node@20.14.14)(typescript@5.5.4)
-      yaml: 2.3.1
+      yaml: 2.7.1
     dev: true
 
   /postcss-load-config@4.0.2(postcss@8.5.3)(ts-node@10.9.1):
@@ -34548,11 +34548,6 @@ packages:
     engines: {node: '>=18'}
     dev: false
 
-  /yaml@2.3.1:
-    resolution: {integrity: sha512-2eHWfjaoXgTBC2jNM1LRef62VQa0umtvRiDSk6HSzW7RvS5YtkabJrwYLLEKWBc8a5U2PTSCs+dJjUTJdlHsWQ==}
-    engines: {node: '>= 14'}
-    dev: true
-
   /yaml@2.7.1:
     resolution: {integrity: sha512-10ULxpnOCQXxJvBgxsn9ptjq6uviG/htZKk9veJGhlqn3w/DxQ631zFF+nlQXLwmImeS5amR2dl2U8sg6U9jsQ==}
     engines: {node: '>= 14'}